dlmalloc-2.6.4.c

eCos/RedBoot for勤研ARM AnywhereII(4510) 含全部源代码

static unsigned int max_n_mmaps = 0;
static unsigned long mmapped_mem = 0;
static unsigned long max_mmapped_mem = 0;



/* 
  Debugging support 
*/

#if DEBUG


/*
  These routines make a number of assertions about the states
  of data structures that should be true at all times. If any
  are not true, it's very likely that a user program has somehow
  trashed memory. (It's also possible that there is a coding error
  in malloc. In which case, please report it!)
*/

#if __STD_C
static void do_check_chunk(mchunkptr p) 
#else
static void do_check_chunk(p) mchunkptr p;
#endif
{ 
  INTERNAL_SIZE_T sz = p->size & ~PREV_INUSE;

  /* No checkable chunk is mmapped */
  assert(!chunk_is_mmapped(p));

  /* Check for legal address ... */
  assert((char*)p >= sbrk_base);
  if (p != top) 
    assert((char*)p + sz <= (char*)top);
  else
    assert((char*)p + sz <= sbrk_base + sbrked_mem);

}


#if __STD_C
static void do_check_free_chunk(mchunkptr p) 
#else
static void do_check_free_chunk(p) mchunkptr p;
#endif
{ 
  INTERNAL_SIZE_T sz = p->size & ~PREV_INUSE;
  mchunkptr next = chunk_at_offset(p, sz);

  do_check_chunk(p);

  /* Check whether it claims to be free ... */
  assert(!inuse(p));

  /* Unless a special marker, must have OK fields */
  if ((long)sz >= (long)MINSIZE)
  {
    assert((sz & MALLOC_ALIGN_MASK) == 0);
    assert(aligned_OK(chunk2mem(p)));
    /* ... matching footer field */
    assert(next->prev_size == sz);
    /* ... and is fully consolidated */
    assert(prev_inuse(p));
    assert (next == top || inuse(next));
    
    /* ... and has minimally sane links */
    assert(p->fd->bk == p);
    assert(p->bk->fd == p);
  }
  else /* markers are always of size SIZE_SZ */
    assert(sz == SIZE_SZ); 
}

#if __STD_C
static void do_check_inuse_chunk(mchunkptr p) 
#else
static void do_check_inuse_chunk(p) mchunkptr p;
#endif
{ 
  mchunkptr next = next_chunk(p);
  do_check_chunk(p);

  /* Check whether it claims to be in use ... */
  assert(inuse(p));

  /* ... and is surrounded by OK chunks.
    Since more things can be checked with free chunks than inuse ones,
    if an inuse chunk borders them and debug is on, it's worth doing them.
  */
  if (!prev_inuse(p)) 
  {
    mchunkptr prv = prev_chunk(p);
    assert(next_chunk(prv) == p);
    do_check_free_chunk(prv);
  }
  if (next == top)
  {
    assert(prev_inuse(next));
    assert(chunksize(next) >= MINSIZE);
  }
  else if (!inuse(next))
    do_check_free_chunk(next);

}

#if __STD_C
static void do_check_malloced_chunk(mchunkptr p, INTERNAL_SIZE_T s) 
#else
static void do_check_malloced_chunk(p, s) mchunkptr p; INTERNAL_SIZE_T s;
#endif
{
  INTERNAL_SIZE_T sz = p->size & ~PREV_INUSE;
  long room = sz - s;

  do_check_inuse_chunk(p);

  /* Legal size ... */
  assert((long)sz >= (long)MINSIZE);
  assert((sz & MALLOC_ALIGN_MASK) == 0);
  assert(room >= 0);
  assert(room < (long)MINSIZE);

  /* ... and alignment */
  assert(aligned_OK(chunk2mem(p)));


  /* ... and was allocated at front of an available chunk */
  assert(prev_inuse(p));

}


#define check_free_chunk(P)  do_check_free_chunk(P)
#define check_inuse_chunk(P) do_check_inuse_chunk(P)
#define check_chunk(P) do_check_chunk(P)
#define check_malloced_chunk(P,N) do_check_malloced_chunk(P,N)
#else
#define check_free_chunk(P) 
#define check_inuse_chunk(P)
#define check_chunk(P)
#define check_malloced_chunk(P,N)
#endif



/* 
  Macro-based internal utilities
*/


/*  
  Linking chunks in bin lists.
  Call these only with variables, not arbitrary expressions, as arguments.
*/

/* 
  Place chunk p of size s in its bin, in size order,
  putting it ahead of others of same size.
*/


#define frontlink(P, S, IDX, BK, FD)                                          \
{                                                                             \
  if (S < MAX_SMALLBIN_SIZE)                                                  \
  {                                                                           \
    IDX = smallbin_index(S);                                                  \
    mark_binblock(IDX);                                                       \
    BK = bin_at(IDX);                                                         \
    FD = BK->fd;                                                              \
    P->bk = BK;                                                               \
    P->fd = FD;                                                               \
    FD->bk = BK->fd = P;                                                      \
  }                                                                           \
  else                                                                        \
  {                                                                           \
    IDX = bin_index(S);                                                       \
    BK = bin_at(IDX);                                                         \
    FD = BK->fd;                                                              \
    if (FD == BK) mark_binblock(IDX);                                         \
    else                                                                      \
    {                                                                         \
      while (FD != BK && S < chunksize(FD)) FD = FD->fd;                      \
      BK = FD->bk;                                                            \
    }                                                                         \
    P->bk = BK;                                                               \
    P->fd = FD;                                                               \
    FD->bk = BK->fd = P;                                                      \
  }                                                                           \
}


/* take a chunk off a list */

#define unlink(P, BK, FD)                                                     \
{                                                                             \
  BK = P->bk;                                                                 \
  FD = P->fd;                                                                 \
  FD->bk = BK;                                                                \
  BK->fd = FD;                                                                \
}                                                                             \

/* Place p as the last remainder */

#define link_last_remainder(P)                                                \
{                                                                             \
  last_remainder->fd = last_remainder->bk =  P;                               \
  P->fd = P->bk = last_remainder;                                             \
}

/* Clear the last_remainder bin */

#define clear_last_remainder \
  (last_remainder->fd = last_remainder->bk = last_remainder)






/* Routines dealing with mmap(). */

#if HAVE_MMAP

#if __STD_C
static mchunkptr mmap_chunk(size_t size)
#else
static mchunkptr mmap_chunk(size) size_t size;
#endif
{
  size_t page_mask = malloc_getpagesize - 1;
  mchunkptr p;

#ifndef MAP_ANONYMOUS
  static int fd = -1;
#endif

  if(n_mmaps >= n_mmaps_max) return 0; /* too many regions */

  /* For mmapped chunks, the overhead is one SIZE_SZ unit larger, because
   * there is no following chunk whose prev_size field could be used.
   */
  size = (size + SIZE_SZ + page_mask) & ~page_mask;

#ifdef MAP_ANONYMOUS
  p = (mchunkptr)mmap(0, size, PROT_READ|PROT_WRITE,
		      MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
#else /* !MAP_ANONYMOUS */
  if (fd < 0) 
  {
    fd = open("/dev/zero", O_RDWR);
    if(fd < 0) return 0;
  }
  p = (mchunkptr)mmap(0, size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
#endif

  if(p == (mchunkptr)-1) return 0;

  n_mmaps++;
  if (n_mmaps > max_n_mmaps) max_n_mmaps = n_mmaps;
  
  /* We demand that eight bytes into a page must be 8-byte aligned. */
  assert(aligned_OK(chunk2mem(p)));

  /* The offset to the start of the mmapped region is stored
   * in the prev_size field of the chunk; normally it is zero,
   * but that can be changed in memalign().
   */
  p->prev_size = 0;
  set_head(p, size|IS_MMAPPED);
  
  mmapped_mem += size;
  if ((unsigned long)mmapped_mem > (unsigned long)max_mmapped_mem) 
    max_mmapped_mem = mmapped_mem;
  if ((unsigned long)(mmapped_mem + sbrked_mem) > (unsigned long)max_total_mem) 
    max_total_mem = mmapped_mem + sbrked_mem;
  return p;
}

#if __STD_C
static void munmap_chunk(mchunkptr p)
#else
static void munmap_chunk(p) mchunkptr p;
#endif
{
  INTERNAL_SIZE_T size = chunksize(p);
  int ret;

  assert (chunk_is_mmapped(p));
  assert(! ((char*)p >= sbrk_base && (char*)p < sbrk_base + sbrked_mem));
  assert((n_mmaps > 0));
  assert(((p->prev_size + size) & (malloc_getpagesize-1)) == 0);

  n_mmaps--;
  mmapped_mem -= (size + p->prev_size);

  ret = munmap((char *)p - p->prev_size, size + p->prev_size);

  /* munmap returns non-zero on failure */
  assert(ret == 0);
}

#if HAVE_MREMAP

#if __STD_C
static mchunkptr mremap_chunk(mchunkptr p, size_t new_size)
#else
static mchunkptr mremap_chunk(p, new_size) mchunkptr p; size_t new_size;
#endif
{
  size_t page_mask = malloc_getpagesize - 1;
  INTERNAL_SIZE_T offset = p->prev_size;
  INTERNAL_SIZE_T size = chunksize(p);
  char *cp;

  assert (chunk_is_mmapped(p));
  assert(! ((char*)p >= sbrk_base && (char*)p < sbrk_base + sbrked_mem));
  assert((n_mmaps > 0));
  assert(((size + offset) & (malloc_getpagesize-1)) == 0);

  /* Note the extra SIZE_SZ overhead as in mmap_chunk(). */
  new_size = (new_size + offset + SIZE_SZ + page_mask) & ~page_mask;

  cp = (char *)mremap((char *)p - offset, size + offset, new_size, 1);

  if (cp == (char *)-1) return 0;

  p = (mchunkptr)(cp + offset);

  assert(aligned_OK(chunk2mem(p)));

  assert((p->prev_size == offset));
  set_head(p, (new_size - offset)|IS_MMAPPED);

  mmapped_mem -= size + offset;
  mmapped_mem += new_size;
  if ((unsigned long)mmapped_mem > (unsigned long)max_mmapped_mem) 
    max_mmapped_mem = mmapped_mem;
  if ((unsigned long)(mmapped_mem + sbrked_mem) > (unsigned long)max_total_mem)
    max_total_mem = mmapped_mem + sbrked_mem;
  return p;
}

#endif /* HAVE_MREMAP */

#endif /* HAVE_MMAP */




/* 
  Extend the top-most chunk by obtaining memory from system.
  Main interface to sbrk (but see also malloc_trim).
*/

#if __STD_C
static void malloc_extend_top(INTERNAL_SIZE_T nb)
#else
static void malloc_extend_top(nb) INTERNAL_SIZE_T nb;
#endif
{
  char*     brk;                  /* return value from sbrk */
  INTERNAL_SIZE_T front_misalign; /* unusable bytes at front of sbrked space */
  INTERNAL_SIZE_T correction;     /* bytes for 2nd sbrk call */
  char*     new_brk;              /* return of 2nd sbrk call */
  INTERNAL_SIZE_T top_size;       /* new size of top chunk */

  mchunkptr old_top     = top;  /* Record state of old top */
  INTERNAL_SIZE_T old_top_size = chunksize(old_top);
  char*     old_end      = (char*)(chunk_at_offset(old_top, old_top_size));

  /* Pad request with top_pad plus minimal overhead */
  
  INTERNAL_SIZE_T